The Pulse

Good health in foreign climes

Overseas travel is on the increase - and so is the incidence of infectious diseases like malaria and dengue fever.

Published 02/02/2006

When our parents were young, overseas travel was both a rarity and a luxury. Not these days. Taj Mahal, Angkor Wat? No worries, we can probably do it on our frequent flyer points.

Foreign travel is on the rise. In 2004, more than 760 million people crossed international borders an increase of 73 per cent over the last 15 years. Most were holiday makers, though the big growth was in business travellers and immigrants returning home for a visit.

But cheaper air travel has a downside. Bugs - viruses, bacteria, and parasites - are taking advantage of this increase in human traffic too.

Depending on the destination, up to two-thirds of travellers become sick - most with diarrhoea, skin problems and respiratory infections - on their return.

About eight percent of travellers become sick enough to seek health care during their trip or when they return home. Those most likely to be affected are travellers to developing countries.

Until now we haven't had a clear overall picture of what illnesses travellers get and where they pick them up. Researchers from the London School of Hygiene and Tropical Medicine have collated information from a network of 30 travel-medicine clinics on six continents to get a better picture of how illnesses are spreading amongst travellers worldwide.

They looked at the medical records of 17,353 tourists who returned home from 230 different developing nations and went to a doctor with an illness over the years 1996 to 2004.

They found that travellers' most common diseases were diarrhoeal illnesses (mostly from parasites), skin diseases (mostly from insect bites), and fevers from diseases like malaria and dengue fever.

Malaria was common in travellers to sub-Saharan Africa (particularly West Africa); dengue afflicted many visitors to the Caribbean and Southeast Asia; leishmaniasis was common in those who visited Central America and South America; and typhoid fever in those travellers to south central Asia.

The point about these illnesses is that they're unfamiliar in the travellers' home countries. There was a tendency for people not to be aware of the dangers and prepare for them.

Often the symptoms didn't begin until well after the trip was over. More than one-third of the patients became sick over a month after they got back, and one in 10 fell ill more than six months later. This led to delays in diagnosis, with serious consequences.

In the case of malaria for instance, a late diagnosis can be fatal. Treatment is more effective if started early in the disease, say the researchers. If a patient presents with a fever syndrome, chronic diarrhoea, or an unusual rash, the doctor should ask whether the patient has recently been overseas.

Be prepared

Travellers will spend ages researching hotels and airfares, but often they don't give much thought to their how their health will fare on the trip. Less than half of travellers to high-risk areas seek advice on health issues prior to the trip, the researchers say.

It's not always possible to avoid disease entirely, even if you're well prepared. Thanks to widespread contamination of food and drink with microorganisms in third world countries, up to two-thirds of travellers are likely to get mild traveller's diarrhoea, whatever they do.

But to limit your chances of a serious illness, follow these tips:

Get all the vaccinations done in full and in time before you leave;

Make sure you've filled prescriptions for medications you need to take, like antimalarial drugs;